Hmm - I tried those steps just now, but that seems to put it into 'put a targetting rectacle on faces' mode. As soon as my face is in front of it, the tagetting boxes track my face. Are you using it with a person (e.g. as a webcam)?
Partial (good-enough for me) work-around: While I couldn't find a way to remove the white box or the face-detection boxes, you can use the arrow buttons to move the white box around the display on the T3i. I moved it to the bottom right corner, whic...